CNL-14-133, Third Six-Month Status Report in Response to the March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049)(TAC Nos..

Third Six-Month Status Report in Response to the March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049)(TAC Nos..

ML14247A644
Person / Time
Site:	Sequoyah
Issue date:	08/28/2014
From:	James Shea Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CNL-14-133, EA-12-049, L44 140828 004, TAC MF0864, TAC MF0865
Download: ML14247A644 (12)

Text

L44 140828 004 Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 CNL-14-133 August 28, 2014 10 CFR 2.202 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Sequoyah Nuclear Plant, Units 1 and 2 Facility Operating License Nos. DPR-77 and DPR-79 NRC Docket Nos. 50-327 and 50-328

Subject:

Third Six-Month Status Report in Response to the March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049) for Sequoyah Nuclear Plant (TAC Nos.

MF0864 and MF0865)

References:

1. Letter from TVA to NRC, Tennessee Valley Authority (TVA) - Overall Integrated Plan in Response to the March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049) for Sequoyah Nuclear Plant, dated February 28, 2013 (ML13063A183)

2. Letter from TVA to NRC, First Six-Month Status Report in Response to March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049) for Sequoyah Nuclear Plant, dated August 28, 2013 (ML13247A286)

3. Letter from NRC to TVA, Sequoyah Nuclear Plant, Units 1 and 2 - Interim Staff Evaluation Relating to Overall Intergraded Plan in Response to Order EA-12-049 (Mitigation Strategies) (TAC Nos. MF0864 and MF0865), dated February 19, 2014 (ML14002A109)

U.S. Nuclear Regulatory Commission Page 2 August 28, 2014

4. Letter from TVA to NRC, Second Six-Month Status Report and Revised Overall Integrated Plan in Response to the March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order-EA-12-049) for Sequoyah Nuclear Plant, dated February 28, 2014 On February 28, 2013, the Tennessee Valley Authority (TVA) submitted an Overall Integrated Plan (OIP) in response to the March 12, 2012, Commission Order modifying licenses with regards to requirements for mitigation strategies for beyond-design-basis external events, Order number EA-12-049, for the Sequoyah Nuclear Plant (SQN), Units 1 and 2 (Reference 1). On August 28, 2013, TVA provided the first six-month status report to the OIP (Reference 2).

The OIP submitted in Reference 1 employed a strategy using reactor coolant pump (RCP) low leakage seals. TVA revised its strategy to use the existing conventional RCP seals.

This change in RCP seals required a revision to the OIP submitted by Reference 1. Based on a review of TVAs plan, including the first six-month update, and information obtained through the mitigation strategies audit process, the NRC concluded in its Interim Staff Evaluation that the plan, when properly implemented, will meet the requirements of Order EA-12-049 at SQN, Units 1 and 2 (Reference 3). The Interim Staff Evaluation included open item 3.2.1.6.A. This open item required revision to the Sequence of Events due to use of the conventional RCP seals for reanalysis by the NRC. On February 28, 2014, TVA provided the second six-month status report and revised OIP (Reference 4) which included the required revision to the Sequence of Events due to use of the conventional RCP seals.

In addition, Reference 4 noted that TVA was evaluating potential changes to the capacity and storage locations of the current 3 MW FLEX diesel generators (DGs) as well as use of the current auxiliary feedwater supply tank. It was also noted that any changes to the SQN mitigation strategies resulting from this review would be provided to the NRC in the third six-month status report.

The purpose of this letter is to provide the third six-month status report pursuant to Section IV, Condition C.2, of Reference 1, that delineates progress made in implementing the requirements of Reference 1, including the resulting changes to storage locations of the current 3 MW FLEX DGs and use of the current auxiliary feedwater supply tank.

Specifically, the Enclosure of this letter provides third six-month status report. This status report incorporates the following changes from the revised OIP:

Storage locations for the current 3 MW FLEX DGs has changed from the FLEX Equipment Storage Building (FESB) to the existing Additional Diesel Generator Building (ADGB); and, The site location for the FESB has been changed.

U.S. Nuclear Regulatory Commission Page 3 August 28, 2014 There is no change to the capacity of the 3 MW DGs. Use of the auxiliary feedwater supply tank (AFWST) remains under evaluation. An option is being reevaluated to qualify the existing Condensate Storage Tank as a primary water source in lieu of the AFWST. Any changes to the SQN mitigation strategies resulting from this reevaluation will be provided to the NRC in the fourth six-month status update.

In addition to the changes described previously, the Open Items table in the Enclosure has been updated. Open Items 1 and 2 have been re-opened as indicated in the Enclosure.

Open Items 4 and 11 are closed and the date for Open Item 7 has been revised. The milestone target completion dates have also been updated as shown in the Enclosure.

There are no new regulatory commitments in this letter. If you have any questions regarding this report, please contact Kevin Casey at (423) 751-8523.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 28th day of August 2014.

Respectfully, Digitally signed by J. W. Shea J. W. Shea DN: cn=J. W. Shea, o=Tennessee Valley Authority, ou=Nuclear Licensing, email=jwshea@tva.gov, c=US Date: 2014.08.28 14:20:25 -04'00' J. W. Shea Vice President, Nuclear Licensing

Enclosure:

Tennessee Valley Authority Sequoyah Nuclear Plants Third Six-Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigations strategies for Beyond-Design-Basis External Events cc (Enclosure):

NRR Director - NRC Headquarters NRO Director - NRC Headquarters NRR JLD Director - NRC Headquarters NRC Regional Administrator - Region II NRR Project Manager - Sequoyah Nuclear Plant NRC Senior Resident Inspector - Sequoyah Nuclear Plant

ENCLOSURE TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT THIRD SIX-MONTH STATUS REPORT FOR THE IMPLEMENTATION OF ORDER EA-12-049, ORDER MODIFYING LICENSES WITH REGARD TO REQUIREMENTS FOR MITIGATION STRATEGIES FOR BEYOND-DESIGN-BASIS EXTERNAL EVENTS

ENCLOSURE TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT THIRDSIX MONTH STATUS REPORT FOR THE IMPLEMENTATION OF ORDER EA-12-049, ORDER MODIFYING LICENSES WITH REGARD TO REQUIREMENTS FOR MITIGATION STRATEGIES FOR BEYOND-DESIGN-BASIS EXTERNAL EVENTS Introduction Tennessee Valley Authority (TVA) developed an Overall Integrated Plan (OIP) (Reference 1 in Reference section of this enclosure), for Sequoyah Nuclear Plant (SQN), Units 1 and 2, documenting the diverse and flexible strategies (FLEX), in response to Reference 2. TVA provided the first 6-month status report on August 28, 2013 (Reference 3) and a revised OIP on February 28, 2014 (Reference 4). This attachment provides an update of milestone accomplishments since submittal of the revised OIP (Reference 4), including any changes to the compliance method or schedule.

Milestone Accomplishments The following milestone(s) have been completed since submittal of the revised OIP (Reference 4), and are current as of July 31, 2014.

None Milestone Schedule The following provides an update to Attachment 2 of the OIP. The activity status of each item is provided, as well as any change to the expected completion date has changed. The dates are planning dates subject to change as design and implementation details are developed.

The revised milestone target completion dates do not impact the order implementation date.

Page 2 of 9

Revised Target Activity Target Activity Completion Status Completion Date Date Submit Overall Integrated Plan Feb 2013 Complete Submit 6 Month Updates:

Update 1 Aug 2013 Complete Update 2 Feb 2014 Complete Update 3 Aug 2014 Complete Update 4 Feb 2015 Not Started Update 5 Aug 2015 Not Started Update 6 Feb 2016 Not Started Update 7 Aug 2016 Not Started FLEX Strategy Evaluation Jun 2013 Complete Walk-throughs or Demonstration May 2015 Not Started Perform Staffing Analysis Jun 2014 Not Started Dec 2014 Modifications:

Modifications Evaluation Oct 2013 Complete Unit 1 N-1 Walkdown Oct 2013 Complete Unit 1 Design Engineering Nov 2014 Started Unit 1 Implementation Outage May 2015 Not Started Unit 2 N-1 Walkdown Apr 2014 Complete Unit 2 Design Engineering Nov 2014 Started Unit 2 Implementation Outage Dec 2015 Not Started Storage:

Storage Design Engineering Jul 2014 Started Oct 2014 Storage Implementation Jul 2015 Not Started May 2015 FLEX Equipment:

Procure On-Site Equipment Jan 2015 Started Develop Strategies with RRC Dec 2013 Complete Install Off-Site Delivery Station Apr 2014 Started Mar 2015 Procedures:

PWROG issues FSG guidelines Jun 2013 Complete Create Site Specific FSIs Jun 2014 Started Nov 2014 Create Maintenance Procedures Jun 2014 Started Nov 2014 Training:

Develop Training Plan Jun 2014 Started Nov 2014 Implement Training Dec 2015 Not Started May 2015 Unit 1 FLEX Implementation May 2015 Not Started Unit 2 FLEX Implementation Dec 2015 Not Started Full Site FLEX Implementation Dec 2015 Not Started Submit Completion Report Jan 2016 Not Started Page 3 of 9

Changes to Compliance Method The following is a list of changes made to the information provided in the February 28, 2014, revised OIP (Reference 4). These changes meet the NEI 12-06 compliance method.

x The storage locations for the current 3 MW FLEX diesel generators (DGs) has changed from the FLEX Equipment Storage Building (FESB) to the existing Additional Diesel Generator Building (ADGB). The location of the ADGB is provided on Sketch 1, page 9.

Relocation of the 3 MW DGs has no impact to the 3 MW DGs electrical connections from the previous revised OIP; however, relocation will allow only one 3 MW DG to be in operation at a time due to ventilation restrictions of the ADGB.

x The site location for the FESB has been changed. The FESB will now be located on the west side of the SQN site. See Sketch 1, page 9. Sketch 1 also provides the revised FLEX equipment haul paths as noted.

Need for Relief/Relaxation and Basis for the Relief/Relaxation TVA is evaluating the potential schedule changes to the first units implementing refueling outage resulting from the changes to the compliance methods as described above and the potential use of the existing Condensate Storage Tank as a primary water source to determine if relief/relaxation is needed. Currently, TVA expects to comply with the order implementation date and no relief/relaxation is required at this time.

Open Items from Overall Integrated Plan and NRC Evaluation The following tables provide a summary of the open items documented in the OIP or the NRC Evaluation and the status of each item.

Open Item Description Status Number 1 The current Condensate Storage Tank (CST) is a Re-Opened non-seismic tank that is not missile protected. The site is currently pursuing two options; the An evaluation is underway qualification and hardening of the existing CST or to determine qualification the construction of a new seismically qualified and and hardening of the missile protected CST. One of these options must existing CST is achievable.

be completed before the volume of the CST can be credited.

2 Liquefaction of haul routes for FLEX will be Re-Opened analyzed.

Analysis required on new haul routes due to relocation of the FESB.

Page 4 of 9

Open Item Description Status Number 3 No detailed analysis has been provided regarding Closed initial FLEX fuel supplies to determine a need time for access to 7 day tank supplies or resupply of the Fuel consumption 7 day tanks. It is assumed that each FLEX spreadsheet completed to component is stored with a minimum supply of show that fuel supply of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of fuel at constant operation. This equipment will last seven assumption will need to be assessed once all days.

FLEX equipment has been purchased and equipment specifications are known.

4 No need time has been identified for action to Closed protect containment. This includes actions to mitigate pressurization of containment due to Reference Westinghouse steaming when reactor coolant system (RCS) vent Calculation paths have been established or actions to mitigate LTR-ISENG-14-2, Rev 0, temperature effects associated with equipment for the MAAP Analysis survivability. An evaluation will be provided to prove indefinite containment coping.

5 The Phase 3 equipment staging area has not been Closed determined.

Areas are identified and will be included with the Regional Response Center (RRC) playbook.

6 A strategy for clearing and removing debris will be Closed determined.

Debris removal equipment is identified and storage determined 7 A thorough analysis of the makeup flow rate Started requirements and other equipment characteristics will be finalized during the detailed design phase of Calculation to be complete FLEX. by fall of 2014 8 The need time for spent fuel pool (SFP) cooling Closed actions (deployment of hose, venting, and alignment of makeup) was determined using worst CN-CDME-13-24 case heat loads. This item will continue to be Westinghouse Calculation assessed and later action times may be acceptable. Note that the timing for this step during an outage is different, but resources will be available to complete the required actions.

9 Functional requirements for each of the Phase 3 Started strategies, equipment and components will be completed at a later time and will be provided in the six month updates to the February 28, 2013 submittal.

Page 5 of 9

Open Item Description Status Number 10 Containment temperature instrumentation is only Started available until flood waters enter the technical support center (TSC) inverter or station battery rooms. A method to monitor containment temperature, postflood, will be developed.

11 The heating, ventilation and air conditioning Closed (HVAC) analysis is preliminary, and has not been finalized. Reference HVAC ELAP Analysis SL-012415, Rev 0 12 Verify ability to deploy FLEX equipment to provide Closed core cooling in Modes 5 and 6 with steam generators (SGs) unavailable. Demonstration prior to implementation of the order and included as part of the FLEX strategy (Reference CN-SEE-II-13-26, Rev 0) 13 An evaluation of the impact of FLEX response Open actions on design basis flood mode preparations will be performed. This evaluation will include the potential for extended preparation time for FLEX.

Changes which affect the Integrated Plan will be included in the six month update.

14 Perform an alternate cooling source evaluation. Closed The purpose of this analysis is to examine options to utilize alternate water sources to provide FLEX strategies have both continuous sources of water to maintain key safety primary and secondary functions. cooling sources identified.

15 Perform conceptual hydraulic performance Open analyses. The purpose of this analysis is to conservatively evaluate hydraulic performance of FLEX systems.

16 Develop a mechanical conceptual design report. Open The purpose of this report is to summarize the mechanical conceptual design of the FLEX strategies and identify any required modifications.

17 Develop a electrical conceptual design report. The Open purpose of this report is to summarize the electrical conceptual design of the FLEX strategies and identify any required modifications.

18 Perform an RCS makeup analysis. The purpose of Open this analysis is to define FLEX RCS inventory and shutdown margin for Sequoyah.

19 Perform an SFP evaluation. The purpose of this Open analysis is to evaluate the impact of sloshing and time-to-boil in the SFP after an earthquake.

Page 6 of 9

Open Item Description Status Number 20 Perform a timing and deployment evaluation. The Open purpose of this analysis is to summarize the FLEX timeline for Sequoyah, identify time constraints and provide for the safety function needs.

21 Develop a programmatic control report. The Open purpose of this report is to summarize the need to implement programmatic control of the FLEX program.

22 Evaluate the existing extreme hazard analysis and Open planned Near-Term Task Force (NTTF) Tier 1 activities on FLEX strategies to summarize on-going industry activities and the potential to impact the developed FLEX strategies.

23 The time at which the Forebay volume depletes Open needs to be evaluated to determine the time at which replenishment is required. Based on Reference 10 there is 1,640,000 gallons available in the Forebay. Based on the alternate cooling source evaluation, approximately 640,000 gallons are required at 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> post ELAP. Therefore, it is expected the Forebay volume will supply suction to the TDAFWP for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following the ELAP event and replenishment will be required during Phase 3.

24 Further analysis will be performed to determine the Open required timeline for implementing the 6.9 KV FLEX DGs as an alternate power source for the loads supplied by the 480v FLEX DGs.

25 Complete battery calculations to document Vital Open Battery life of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> after loss of all AC. A battery calculation has been completed for WBN which is of similar design.

26 The CETs are only available until water enters the Closed auxiliary instrument room. A method to monitor CET, post flood, will be evaluated and developed, if CETs will not be required required. for flood event.

27 Strategies to address extreme cold conditions on Closed the refueling water storage tank (RWST) and/or boric acid tanks (BATs), including potential need to Initial RWST Technical reenergize heaters have not been finalized. Specifications temperature requirements ensure that five hours is not challenged.

28 Establish a contract with the SAFER team in Closed accordance with the requirements of Section 12 of Reference 2. Agreement with Regional Response Center (RRC) is in place Page 7 of 9

Potential NRC Evaluation Impacts Use of the auxiliary feedwater supply tank is still under evaluation. An option is being reevaluated to qualify the existing Condensate Storage Tank (CST). Use of the existing qualified CST as a primary water source in the FLEX strategy, has the potential to impact the NRC evaluation.

References The following references support the updates to the OIP described in this enclosure.

1. Letter from TVA to NRC, Tennessee Valley Authority (TVA) - Overall Integrated Plan in Response to the March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049) for Sequoyah Nuclear Plant, dated February 28, 2013 (ML13063A183)

2. NRC Order Number EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events, dated March 12, 2012.

3. Letter from TVA to NRC, First Six-Month Status Report in Response to March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049) for Sequoyah Nuclear Plant, dated August 28, 2013 (ML13247A286)

4. Letter from TVA to NRC, Second Six-Month Status Report and Revised Overall Integrated Plan in Response to the March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049) for Sequoyah Nuclear Plant, dated February 28, 2014 Page 8 of 9

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